Question: The arithmetic sequence $(a_i)$ is defined by the formula: $a_i = 5 - 3(i - 1)$ What is $a_{15}$, the fifteenth term in the sequence?
Answer: From the given formula, we can see that the first term of the sequence is $5$ and the common difference is $-3$ To find $a_{15}$ , we can simply substitute $i = 15$ into the given formula. Therefore, the fifteenth term is equal to $a_{15} = 5 - 3 (15 - 1) = -37$.